Abstract:

Biomorphic porous Si/SiC ceramics were prepared by liquid silicon infiltration-reaction and subsequent removing residual Si. The microstructure morphology and component analysis of the cellular Si/SiC were investigated by means of scanning electron microscope and X-ray diffraction. The porosity and distribution of pore diameter of porous Si/SiC were determined by mercury intrusion method. Results show that the resulting porous ceramic is composed of major crystal phase β－SiC and secondary phase residual free Si. The ceramic composite maintained the original morphology of the wood and exhibited a porosity of 16-32% by controlling the removing Si time. The Archimedes and three-point bending methods were used to test the apparent porosity and bending strength of porous SiC ceramic. The influence of the removing Si time on the final phase composition and mechanic properties of the formed biomorphic Si/SiC ceramic composites is analyzed. The formation mechanism of SiC was also discussed.

Key words: porous silicon carbide ceramics,biotemplating,liquid silicon infiltration processing(LSIP),microstructure,mechanical property